In the realm of nuclear fusion research, accurately monitoring fast-ion behavior is crucial for maintaining plasma performance and preventing damage to reactor components. Researchers from the University of Seville, led by M. Rodríguez-Ramos, have recently investigated the angular emission properties of scintillators, which are widely used detectors in fusion diagnostics. Their work, published in the journal Review of Scientific Instruments, sheds light on the importance of considering angular dependencies in scintillator-based measurements.
Scintillators are materials that emit light when excited by ionizing radiation, making them useful for detecting fast ions in fusion plasmas. However, previous studies often assumed that these materials emit light uniformly in all directions, an assumption that the researchers from the University of Seville sought to test. They focused on two commercial scintillators, TG-Green and b-SiAlON, and irradiated them with 3.5 MeV He++ and 1 MeV D+ beams, which are representative of conditions expected in future fusion devices like ITER.
To measure the detection efficiency as a function of observation angle, the researchers developed a novel experimental setup. This setup combined precise optical alignment, angular scanning, and rigorous calibration. Before characterizing the angular emission, they conducted stability tests and found that the scintillators exhibited negligible radiation-induced degradation under the applied fluences. They also determined that transmission losses due to optical fiber bending were below 1.5%.
The results of the study revealed a pronounced angular anisotropy in the scintillation emission for both materials. The light intensity decreased as the detection angle increased, a trend that could be well described by an empirical cosine-based model. Moreover, the normalized response of the scintillators showed minimal dependence on the ion species or energy. These findings highlight the importance of considering angular dependencies in scintillator-based diagnostics, which can lead to more accurate measurements of fast-ion fluxes in fusion plasmas.
The practical applications of this research are significant for the energy sector, particularly in the development of nuclear fusion as a clean and sustainable energy source. By improving the accuracy of fast-ion measurements, researchers can better understand and control plasma behavior, ultimately enhancing the safety and efficiency of fusion reactors. This work not only advances our knowledge of scintillator properties but also contributes to the broader goal of harnessing fusion energy for practical applications.
Source: Review of Scientific Instruments
This article is based on research available at arXiv.